This invention pertains to the direct preparation of hydridocarbonyl tris (triorganophosphorus)rhodium complex from a concentrate residue which is derived from a spent hydroformylation reaction medium containing deactivated rhodium complex catalyst. More specifically, this invention pertains to the direct preparation of hydridocarbonyl tris (triorganophosphorus) rhodium in high yields from rhodium complex concentrates which are treated with an oxidant and by the following three steps of:
i) rhodium-carbonyl complex synthesis PA1 ii) preparing the hydridocarbonyl tris (triorganophosphorus) rhodium complex PA1 iii) post reaction with carbon monoxide and hydrogen PA1 i) rhodium carbonyl complex synthesis step PA1 ii) hydridocarbonyl tris (triorganophosphorus) rhodium synthesis step PA1 iii) subsequent gas reaction with carbon monoxide and hydrogen
Moreover, this process is distinguished by driect preparation of hydridocarbonyl tris (triorganophosphorus) rhodium in a one-phase organic reaction according to the above described steps without using halogen compounds and product separation in each step.
Hydridocarbonyl tris (triorganophosphorus) rhodium complex can be used as a catalyst in processes such as a hydrogen atom exchange reaction, isomerization, carbonylation and hydroformylation of olefins. Particularly it has excellent catalytic activity and selectivity in hydorformylation of olefins, and thus widely used as commercial processes.
There are several methods for the preparation of hydridocarbonyl tris (triorganophosphorus) rhodium complex.
In general it can be prepared from rhodium trichlorohydrate (RhCl.sub.3.3H.sub.2 O), halocarbonyl bis (triorganophosphorus) rhodium and spent rhodium catalyst from hydroformylation distillate residue as a starting material.
Halocarbonyl bis (triorganophosphorus) rhodium as a starting material and hydrazine reduction method under ethanol solvent was disclosed in J. Amer. Chem. Soc., 85, 3500, 1963. Chem. Commun., 305, 1967 discloses that chlorocarbonyl bis (triphenylphosphine) rhodium complex was prepared by reacting with sodium tetrahydridoborate (NaBH.sub.4) or a triethyl amine and hydrogen reaction under an ethanol solvent which contains excessive triphenylphosphine. It is also known in Inorg, Synth, 28, 81, 1990 that rhodium trichlorohydrate is converted by reaction with KOH, HCHO under ethanol solvent which contains triphenylphosphine. The yield of this reaction was 95%.
However, the preparation of hydridocarbonyl tris (triorganophosphorus) rhodium from rhodium complex, derived from a spent hydroformylation medium, is much more difficult than above preparation methods which use pure chemical grade. Furthermore, such rhodium complex, deactivated through various routes during hydroformylation reaction, may cause more difficulty in converting to hydridocarbonyl tris (triorganophosphorus) rhodium.
EP 0, 055, 487 describes the preparation of hydridocarbonyl tris (triorganophosphorus) rhodium by converting halocarbonyl bis (triorganophosphorus) rhodium through hydrogenation with sodium tetrahydroborate (NaBH.sub.4). In this process halocarbonyl tris (triorganophosphorus) rhodium was prepared by reacting a hydroformylation reaction medium with HCl and DMF. The reaction yield was 86.6%.
U.S. Pat. No. 4,446,074 discloses the synthesis of hydridocarbonyl tris (triorganophosphorus) rhodium by reacting a hydroformylation reaction medium and KOH under ethanol solvent and subsequent treatment with syngas. However, a low recovery yield, 48%, was observed in this process. U.S. Pat. No. 4,113,754 describes the preparation process of hydridocarbonyl tris (triorganophosphine) rhodium from chlorocarbonyl bis (triorganophosphine) rhodium which was prepared from a hexachlororodate solution, tertiary phosphine, and carbonmonoxide. In this process the spent hydroformylation medium was treated with mineralic acid and peroxide compounds containing oxygen. Subsequently, the obtained water soluble rhodium salts and rhodium complex can be recovered by passing an aqueous solution in cation exchange resin. Hexachlorodate solution can be isolated by employing a hydrogen chloride aqueous solution. However, this process requires an aqueous phase and needs excessive mineralic acid and hydrogen chloride aqueous solution.